Power transfer between a source resonator and a capture resonator of a wireless power transfer system is usually initiated after a wireless communication link is established between a transmitter controller off-board the vehicle and a receiver controller on-board the vehicle. The power transfer between the power source and the load must be controlled so that the power source supplies no more energy than the load is capable of using. The receiver controller communicates with the transmitter controller to negotiate an energy transfer rate that can be accepted by the load.
It may be desirable to initiate the power transfer at some time after the vehicle has been parked near the source resonator, for instance to take advantage of off-peak electrical energy prices. In order to do this, the receiver controller must be capable of establishing communication with the transmitter controller. Therefore, the receiver controller must be maintained in a powered state or in a low power stand-by state that can respond to the transmitter controller. In either of these examples, the receiver controller requires power to be supplied from the vehicle batteries.
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.